The present invention relates to a device for causing the release of an object, particularly a prosthesis, into a human passage or animal passage and to an implantation system comprising such a device and a catheter carrying the object.
Although not exclusively, the present invention applies more particularly to the implanting of a prosthesis in an artery of the human body, especially in the abdominal aorta.
It is known that the implantation of arterial prostheses, such as those disclosed for example in documents EP-0 461 791, WO-95/21592 and EP-0 880 948, is generally performed using a catheter which in particular, and in the known way, comprises:
a carrying sheath which, at its distal part, comprises dilating means, for example a dilation tip with or without an inflatable balloon, and which carries said prosthesis;
a pushing intermediate sheath which partially surrounds said carrying sheath and which can slide with respect to the latter; and
a protective outer sheath which at least partially covers the distal end of said carrying sheath, which partially surrounds said intermediate sheath, and which can slide with respect to the latter.
In the known way, implanting the prosthesis in an artery generally involves the following three successive stages, which may, in particular, be monitored by radiography, for example by providing radio-opaque elements on the catheter and/or the prosthesis:
an initial stage, during which the prosthesis is brought at least close to its future location in the artery, using the catheter, the aforementioned three sheaths of which are secured together. By way of an illustration, to implant a bifurcated aortic prosthesis, for example of the type described in document EP-0 461 791, in the abdominal aorta between the iliac arteries and the renal arteries, the catheter is generally entered into the human body at the femoral arteries, and the distal part of said catheter, which carries the prosthesis, is brought into the aorta via the iliac arteries;
a release stage, during which the prosthesis is released into the artery. To do this, the protective outer sheath has, in particular, to be slid with respect to the intermediate sheath so that said outer sheath releases the distal part of the catheter, particularly the region in which the prosthesis is located; and
a stage of withdrawing the catheter from the human body.
The present invention is concerned more specifically, although not exclusively, with said release stage.
In general, to carry out this release stage, the surgeon implanting the prosthesis, or one of his assistants, manually slides the outer sheath with respect to the intermediate sheath by taking hold of two extracorporal parts of said sheaths, so as to release the prosthesis as discussed hereinabove.
As this operation is performed manually and thus, in general, jerkily, this sliding (and therefore also the release of the prosthesis) is imprecise and uneven. What is more, it is difficult, and sometimes even impossible, to achieve because:
the sheaths are generally slippery; and, above all,
it is necessary to produce a great deal of force, particularly to release large prostheses, such as the aforementioned bifurcated aortic prostheses.
The object of the present invention is to overcome these drawbacks. This invention relates to a device allowing an object, particularly a prosthesis, to be released easily in a human or animal passage in a precise and jerk-free way carrying no risk of injuring said passage, said object being carried and delivered into said human passage or animal passage by a catheter which comprises a first sheath and a second sheath (an intermediate sheath and a protective outer sheath in the aforementioned example) which are partially introduced into said passage, mounted telescopically and able to slide one with respect to the other, which catheter releases said object in response to an appropriate relative sliding of said first and second sheaths.
To this end, according to the invention, said device is noteworthy in that it comprises:
a casing;
first fixing means capable of fixing an extracorporal part of said first sheath to said casing;
a mobile carriage mounted on said casing so that it can be moved with respect thereto;
second fixing means capable of fixing an extracorporal part of said second sheath to said mobile carriage; and
controllable drive means capable of moving said mobile carriage with respect to said casing.
Thus, by virtue of the invention, the relative sliding of said first and second sheaths is performed by the device according to the invention. More specifically, this sliding is brought about by moving the mobile carriage (to which one sheath is fixed) with respect to the casing (to which the other sheath is fixed). This is achieved automatically or by generating a small force (depending on the embodiment of drive means considered, as specified hereinbelow) with nothing in common with the aforementioned force that has customarily to be exerted by a surgeon without the use of the device according to the invention.
In consequence, as will be seen in greater detail hereinbelow, the object may be released:
continuously and smoothly, that is to say without jerkiness;
without the risk of injuring the passage; and
very precisely,
and this can be achieved purely and simply by mastering the movement of said mobile carriage.
In the context of the present invention, the drive means used for this purpose may be produced in different ways.
In particular, and advantageously:
in a first embodiment, said drive means comprise an endless screw which collaborates with a tapping made in the carriage and which is moved by a controllable motor;
in a second embodiment, said drive means comprise a rack system which acts on the carriage and which is also moved by a controllable motor;
in a third embodiment, said drive means comprise:
an elastic means, preferably a spring, which is mounted so that it is elastically constrained between the casing and the carriage so as to be able to move the latter with respect to said casing; and
a controllable stop capable of preventing the movement of said mobile carriage with respect to said casing; and
in a fourth embodiment, said drive means comprise a lever system which can be actuated or controlled manually.
Furthermore, in said first and second embodiments, said motor, preferably a battery-powered or mains-powered electric motor, may be controlled automatically by a programmable element, for example an electronic chip. In this case, the release stage may be performed automatically, according to a pre-established program.
Furthermore, advantageously, said carriage is mounted so that it can move on guide rails, preferably rectilinear guide rails, secured to said casing.
What is more, according to the invention and advantageously, the casing of said device:
has a transparent window allowing part (located inside said casing) of at least one of said sheaths to be seen from the outside, which makes it possible to visually monitor the relative sliding of the two sheaths, and therefore the progress of the stage of releasing said object; and/or
is made in two parts which are at least partially separable and which can be secured together, which makes it easy to mount a catheter in said casing and therefore in the device according to the invention; and/or
has an elongate shape comprising a handgrip region tailored to the hand of someone using said device, which in particular makes said device easier to hold in the hand and manipulate.
The present invention also relates to a system for implanting an object, particularly a prosthesis, in a human passage or animal passage, particularly in an artery.
According to the invention, said system is noteworthy in that it comprises:
a catheter which:
carries and delivers said object into said human passage or animal passage;
comprises a first sheath and a second sheath which can be partially introduced into said passage, mounted telescopically and able to slide one with respect to the other; and
releases said object in response to an appropriate relative sliding of said first and second sheaths; and
a device like the aforementioned one, for causing the release of said object in said human passage or animal passage by causing said relative sliding of the first and second sheaths.
Furthermore, advantageously, at least one of said sheaths comprises an anti-reflux valve, which makes it possible, when implanting in an artery or blood vessel, to prevent blood from flowing out of said artery or blood vessel via said catheter.
Furthermore, advantageously, said anti-reflux valve is capable of collaborating with fixing means of the device according to the invention, to improve and simplify the fixing of the first and second sheaths to said device.
What is more, to make it easier to visually monitor the release stage, for example through a transparent window in the casing, like the aforementioned one, at least one of said sheaths, preferably the intermediate sheath, advantageously has at least one graduation of the conventional type on its external face.